Synthetic resins, which have excellent features, are generally used in various applications such as molded articles and films. However, a synthetic resin product is highly prone to be electrostatically charged due to its hydrophobicity, and therefore has many drawbacks such as foreign matter and dust adhering to the product to deteriorate the appearance, an electrical problem that occurs during processing, and a malfunction that occurs when the product is used in electronic equipment.
Conventionally, in order to solve these drawbacks, a method of adding various surfactants such as anionic surfactants, cationic surfactants, and nonionic surfactants has been practically used. This method of adding a surfactant gives an excellent antistatic property to the product for a short period of time after formation thereof; however, it is difficult to preserve such property for a long period of time because a surfactant that had bled out on the surface of the product is lost by friction, washing with water, or the like. Furthermore, the synthetic resin product is subjected to a high temperature during formation, which causes thermal decomposition of a part of the surfactant. This leads to smoking during formation, discoloration of the product, and the like. In a multilayer film and sheet of a synthetic resin, an antistatic agent must be added not only to a surface layer but also to a core layer for antistatic performance, resulting in an increase of the addition amount thereof, which is economically disadvantageous.
In recent years, in order to solve these drawbacks and problems involved in surfactant use, a polymer antistatic agent in which polyetheresteramide as a main component and an acid-modified polyolefin and the like as a third component are mixed (Patent Document 1) and a polymer antistatic agent having a cationized maleimide structure (Patent Document 2) are suggested, none of which, however, has adequate performance. A polymer antistatic agent in which a modified polyolefin and a multifunctional hydrophilic group are copolymerized (Patent Documents 3, 4) is also suggested, which has, however, a problem of being inconsistent in its performance in a film and a sheet although being effective in a molded article. In particular, in the case of using the film as a component in a touch panel, a polarizer, or the like, high optical uniformity is required of the film. However, the film has inadequate appearance and transparency with a streak, fish eye, and/or the like.